21115643522 has 8 divisors (see below), whose sum is σ = 31674088956. Its totient is φ = 10557613872.

The previous prime is 21115643513. The next prime is 21115643587. The reversal of 21115643522 is 22534651112.

It can be written as a sum of positive squares in 2 ways, for example, as 20813544361 + 302099161 = 144269^2 + 17381^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 116648 + ... + 236300.

Almost surely, 2^21115643522 is an apocalyptic number.

21115643522 is a deficient number, since it is larger than the sum of its proper divisors (10558445434).

21115643522 is a wasteful number, since it uses less digits than its factorization.

21115643522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207892.

The product of its digits is 14400, while the sum is 32.

The spelling of 21115643522 in words is "twenty-one billion, one hundred fifteen million, six hundred forty-three thousand, five hundred twenty-two".